Generally, portable terminals refer to apparatuses allowing a user to enjoy various contents while carrying them, such as a portable communication apparatus, an MP3 player, a Portable Multimedia Player (PMP), an electronic book, and so forth.
A case of the portable terminal can be visually checked by the user, and it is natural that the user choose a portable terminal having an elegant design and a high-quality exterior among portable terminals having similar functions. In particular, with the recent spread of a bar-type portable terminal, a large display is disposed on a front surface of the portable terminal and a battery cover for covering a battery is disposed on a rear surface thereof. The battery cover of the portable terminal is manufactured with plastic, a magnesium alloy, an aluminum alloy, etc. By nature of the portable terminal, the battery cover has to have light weight and good abrasion resistance, shock resistance, and yield strength. Moreover, in the rear surface of the portable terminal, that is, the battery cover, a material which does not affect antenna radiation performance, such as plastic, is used in the periphery of the antenna to secure antenna radiation performance. For example, when the battery cover is implemented with a metallic material, antenna radiation performance is not sufficiently secured. Therefore, conventionally, in a battery cover portion at a position in which the antenna is installed, an injection material, such as Polycarbonate (PC), urethane, etc., is applied to a portion of metals. As a result, the battery cover can be divided into the first region using metallic material and the second region using injection material, such as PC, urethane, or the like, for the second region requiring antenna radiation in correspondence to positions in which antennas are installed. A conventional battery cover is disclosed in a Korean Patent Application Publication No. 10-2010-0058116 (published on Jun. 3, 2010 and entitled “Battery Pack for Portable Terminal”).
FIG. 1 is a view schematically showing a structure of a conventional battery cover, and FIG. 2 is a view schematically showing a cross-section cut along a line A-A′ of FIG. 1 and antenna radiation performance thereof. With Reference to FIGS. 1 and 2, to avoid an influence upon antenna radiation performance, a metallic material cannot be used in a portion of a battery cover 11, specifically, a portion of the battery cover 11 in a position where an antenna is built in to implement antenna radiation capability, thus, an injection material region 11a such as PC, urethane, etc., is disposed in that portion of the battery cover 11. That is, when the antenna is installed in upper and lower positions of the portable terminal, a metallic material region 11a in which antenna radiation is limited (a region ‘N’ in FIG. 2) is formed in a center portion of the battery cover 11, and the injection material region 11a in which antenna radiation is possible (a region ‘Y’ in FIG. 2) is provided in an antenna mounting position above and below the metallic material region 11a. However, that the battery cover 11 is divided into the injection material region 11a and the metallic material region 11a, causes design constraints and degrading sophistication to a portable terminal with a metallic material.